1. Field of the Invention
The present invention relates to a pre-tensioning mechanism in which a rotating member is rotated and a take-up member is rotated in a take-up direction by a moving member being moved.
2. Related Art
In a seat belt take-up device described in Japanese Patent Application Laid-Open (JP-A) No. 8-207706, a piston rod is moved, and a teeth portion of the piston rod meshes with a teeth portion of a toothed ratchet, thereby rotating the toothed ratchet in the take-up direction and taking up a seat belt by the retractor rotating in the take-up direction.
In the seat belt take-up device therein, it is recognized that the retractor is made capable of rotating integrally with the toothed ratchet even at a time before the piston rod is moved. It is accordingly may be possible that, in a state in which a large rotational force in a pull-out direction (the direction opposite to the take-up direction) is applied through the seat belt and the retractor to the toothed ratchet from an occupant of a vehicle wearing the seat belt, sticking-in (digging-in) of the toothed portion of the piston rod and the toothed portion of the toothed ratchet occurs due to the meshing of the toothed portion of the piston rod with the toothed portion of the toothed ratchet. This consequently gives rise to the possibility of a loss in a force transmitted from the piston rod to the toothed ratchet.